The HTC Titan’s monster screen is perfect for Windows Phone 7

Smartphone screens come in all sizes, including some that are so large that they could be considered small tablets. Big screens are attractive to those who value lots of display real estate, but they have serious downsides: they’re battery hogs, require serious graphics muscle and can be ergonomically uncomfortable.

Personally, I prefer smaller screens – it’s one reason I carry an iPhone. But I’ve been playing with a big-screen smartphone that I could live with, largely because the operating system suits a big screen.

The HTC Titan uses Windows Phone 7.5, a.k.a. Mango, and it’s available from AT&T. The name Titan is apt: it’s got a whopping 4.7 inch display in a case that 5.18-by-2.78 inches. It’s slightly larger than Samsung Galaxy S II, but it feels much more solid, thanks to an aluminum body.

While the screen is huge, the resolution is not – it’s 480-by-800 pixels. As a result, while the is a lot of display space, the amount of information it can show on a single screen is limited. This would be all kinds of ugly on an Android device, but with Windows Phone, it’s not bad at all.

That’s because Microsoft’s operating system uses oversized text as a design element. The smaller resolution on a bigger screen makes the text very easy to read. In addition, the use of tiles instead of icons works better on a bigger screen – they’re easier to tap and manipulate, making up for the ergonomic drawback of a big phone.

One of the dilemmas of an oversized smartphone is that it’s hard to tap and type with one hand, which is usually done by using your thumb to reach the different regions of the screen. On some big phones, it’s very difficult for many people to reach the full width of a screen. I’ve got average-sized hands, and I find using Android devices like the Galaxy S II, which has a 4.52-inch screen, difficult at best.

And while the Titan does require more of a stretch than my iPhone, the layout of the Windows Phone interface makes it easier to hit my targets on the far edges of the screen. See the images below.

The size and placement of the tiles make all the difference.

I tend to carry my smartphones in my shirt pocket, and while the Titan certainly isn’t as compact as my iPhone, it fits well. It’s solid but not so heavy that it looks weird in my shirt.

It’s also a decent performer. The Titan has a single-core, 1.5-GHz processor, but Windows Phone is snappy by nature and performs quite well. It comes with 16 gigabytes of storage, but unfortunately there’s no memory-card slot so it’s not expandable. It also has an 8-megapixel rear camera capable of shooting 720p HD video, and a front-facing, 1.3-megapixel camera.

The battery life on this phone is about what you’d expect on a large-screen device – I was lucky to make it through a full day on a charge with moderate use.

The Titan works on AT&T’s “Faux G” HSPA+ network, which means you can expect speeds in Houston that are about the same as 3G speeds. In my speed tests, this phone never was any faster than my 3G iPhone 4.

I’m becoming a real fan of Windows Phone, and here’s a device on which it really shines. If HTC improved the Titan with LTE, memory-card storage and better battery life, I’d be sorely tempted to defect . . . depending, of course, on what Apple does with the iPhone 5.